| 摘要 |
An electric power assisted steering system comprising a steering mechanism which operatively connects a steering wheel to the road wheels of the vehicle, a torque sensing means ( 6 ) adapted to produce a first output signal indicative of the torque carried by a portion of the steering mechanism ( 7 ), a means ( 6 ) for producing a second output signal indicative of the angular velocity of the steering wheel, a difference means ( 21 ) for determining the difference in value of the torque carried by a portion of the column between two points in time to produce a third output value, an electric motor ( 1 ) operatively connected to the steering mechanism, a signal processing unit ( 7 ) adapted to receive the two signals and to produce a torque demand signal representative of a torque to be applied to the steering mechanism by the motor ( 1 ), and a motor drive stage adapted to provide a drive current to the motor ( 1 ) responsive to the torque demand signal, and in which the torque demand signal ( 1 ) includes a damping component that is dependent upon both the first output signal, the second output signal and the third output signal. |
